All this talk about whiteboards has triggered a question I have about
blackboards. In high school, my teacher had a thin square pad, about 1
meter on a side, with many tiny holes in it. When he placed the pad
against the blackboard and rubbed a chalk-filled eraser over the surface,
the chalk bled through the
holes and formed a nice grid (made up of little dots) on the blackboard.
I have asked numerous vendors and manufacturers for this product and not
been able to find it.
Am I remembering incorrectly? Have you seen this kind of thing before?
Mark J. Lattery Phone: (920)424-7105
Assistant Professor of Physics Dept: (920)424-4433
Department of Physics and Astronomy Fax: (920)424-0894
University of Wisconsin Oshkosh Email: lattery@uwosh.edu
800 Algoma Boulevard
Oshkosh, Wisconsin 54901-8644
"Physical concepts are the free creations of the human mind and
are not, however it may seem, uniquely determined by the external world."